I've wondered a bit about the name "French drain" but didn't look it up until this morning.

French drain - Wikipedia, the free encyclopedia

These were described and popularised by Henry F. French (1813-1885) a lawyer and Assistant US Treasury Secretary from Concord, Massachusetts in his book "Farm drainage."

French, Henry F. (1859). Farm drainage: the principles, processes, and effects of draining land with stones, wood, plows, and open ditches, and especially with tiles. New York: Orange Judd & Company.